Health-related behaviors are now considered one of the primary reasons for poor health outcomes, such as cardiovascular disease, cancer, and premature mortality (McGinnis & Foege, 1993). One of the keys to improving health is identifying the antecedents to health behaviors, which fall into the superordinate categories of individual differences, such as personality traits, and social environmental factors, such as low socioeconomic status (Adler & Mathews, 1994). At the time of our last grant submission, the personality trait of conscientiousness-individual differences in the propensity to be self-controlled, organized, planful, and norm following-had not been systematically integrated into research on the health process. With the support of grant R01AG21178 we initiated a program of research, including two longitudinal studies, to examine the role of conscientiousness in the health process. In the last five years we have shown that conscientiousness predicts all risky and preventative health behaviors that affect physical health and mortality. That conscientiousness also predicts many of the social environmental factors that contribute to positive health outcomes. And that conscientiousness, health behaviors, and social environmental factors are reciprocally related to one another over time. Based on this program of research, it is clear that conscientiousness plays a significant role in determining positive health outcomes across the life course, including old age. With this foundation of research in place, we propose to pursue 4 aims for the current competing renewal of R01AG21178: 1) test the effect of genetic polymorphisms on conscientiousness, health behaviors, social environmental factors and their associations, 2) extend the longitudinal studies to incorporate the effect of conscientiousness, health behaviors and social environmental factors on physical health and mortality, 3) continue our longitudinal research initiated as part of the grant into the interplay of conscientiousness, health behaviors, and social environmental factors over time, permitting us to test the predictive validity of conscientiousness in a prospective longitudinal design, and 4) determine the specific social cognitive, behavioral, and emotional mechanisms that explain the relation of conscientiousness to health.